Voltage-Gated Sodium Channel Inactivation

Inactivation vs. Other States: It's crucial to distinguish inactivation from other states of ion channels (e.g., closed, open, desensitized). Inactivation is a specific mechanism that prevents further ion flow even when the channel's general structure might appear "open."
Mechanism of Inactivation: During the process of inactivation, voltage-gated sodium channels, which initially open to allow sodium entry, slowly inactivate.
Physical Analogy: Imagine the channel's pore (the pathway for ions) is structurally open, but a physical blocker – like a "bouncer" – moves into place and obstructs the pathway. This bouncer prevents ions from passing through, effectively stopping the flow despite the channel's overall open shape.